A mechanical arm has typically similar functions to a human arm. The arm may be the whole mechanism or may be part of a more complex robot. There are a various mechanical arms which may be used by twisting their spatial position which are adapted to maintain their last position.
U.S. Pat. No. 4,551,061 describes a robot arm formed of a bundle of adjacent elastomeric tubes supplied independently with fluid pressure to force bending, extension or contraction. The tubes are maintained in parallel alignment by means of spaced apart parallel ribs through which the tubes pass. Parallel, spaced apart, rods extending through the ribs, but fixed at one end, have opposite free ends passing into position sensors. Bending and lengthwise changes in arm position may be sensed by the rods and used to control pressure in individual arms to correct or change arm position. In other words, the solution provided by this publication teaches applying fluid pressure enables the robot arm to bend at a certain curvature radius by applying a fluid pressure via the elastomeric tubes, and by the use of this pressure, to obtain the required bending, extraction or contraction.
However, one of the major problems associated with mechanical arms as known in the art lies with the fact that it is not easy, if not impossible, to have a mechanical arm flexible enough so that it would be bent to a desired shape and once the desired shape is reached, turning the mechanical arm into a rigid structure, thereby ensuring that it retains its bent desired shape for any required period of time.
Some other solutions are known in the art that provide an arm which may be bent to a desired shape and once the desired shape is reached, retain the desired shape. For example, a flexible/adjustable, hollow support arm of a reading lamp, a balanced-arm lamp which is a lamp that can be moved into any position, and the springs comprised therein will maintain its position until moved again, flexible cooling water conduits for CNC machines, etc. These flexible arms are made of a plurality of joints that are interlocked in a twisted position due the friction developed therebetween while changing the arms' shape (i.e. when the arm is twisted).
The present invention seeks to provide a novel device, which may be used as and/or be incorporated in a mechanical arm, while overcoming drawbacks of prior art solutions.